BioMed Analysis: Joining forces against TB

A partnership involving the US Food and Drug Administration may speed up delivery of new tuberculosis drug combinations, says Priya Shetty.

This year's World Tuberculosis (TB) day on 24 March marks a critical halfway point in the Global Plan to Stop TB, launched by the Stop TB Partnership in 2006 to eliminate the disease by 2015.

The plan already has some success — the global incidence rate of TB is slowly falling, and in 2008 the treatment rate exceeded the 85 per cent target for the first time in more than a decade.

But more than two billion people — about a third of the world's population — are still infected with the TB bacterium, and each year the disease kills 1.8 million people.

A key development in the global fight against TB, launched this week, could prove to be the Critical Path to TB Drug Regimens (CPTR), a public-private partnership designed to speed up the development and approval of new treatments.

The initiative has a good pedigree — its founders are the Bill & Melinda Gates Foundation, the TB Alliance, the Critical Path Institute (C-Path) and six major pharmaceutical companies.

But, more importantly, it is being co-launched by the US Food and Drug Administration (FDA), which could also mean a new approach for fast-tracking drug development for diseases of the poor.

Need for TB drugs

New TB drugs are desperately needed. The existing treatment is a cocktail of drugs that must be taken over 6–8 months. Often, one of the biggest challenges facing healthcare professionals is simply ensuring that their patients finish the course of treatment.

Another growing challenge is the increasing number of people infected with TB who are also living with HIV. In 2008, 15 per cent (1.4 million) of the 9.4 million new TB cases were in people also infected with HIV.

TB is a leading killer of people with HIV — up to half the deaths of HIV/AIDS patients result from TB and a person with both diseases can be four times more likely to die during TB treatment than someone infected with TB alone (see Tuberculosis: Facts & figures).

The emergence of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB), where patients cannot be treated with first-line drugs (or, in the case of XDR-TB, more expensive second-line drugs), further underscores the need for a new generation of TB drugs.

The last first-line drug approved for TB was rifampicin in the 1960s. And although there are several drugs in the pipeline — for example, the Stop TB Partnership hopes to introduce a new drug later this year — the prospects for new drug combinations have been less good.

This is where CPTR could make an impact. Sharing data among the CPTR partners could allow several TB drugs in development to be tested in combinations rather than individually. A treatment combination could be ready in a much shorter time than if each drug is first developed separately.

Role of the FDA

This is not the first data-sharing initiative for revitalising a flagging area of research and development in global health. Attempts to spur new drugs include the Open Source Drug Discovery database, led by India's Council of Scientific and Industrial Research, and launched in 2008 initially for TB.

But with the FDA on board and keen to "validate the appropriate tools to approve new combinations of TB therapies", the CPTR could deliver faster results and kickstart a new regulatory approach to harnessing collaborative know-how for practical solutions.

Indeed, clinical trials of new combinations could be launched by the end of this year.

Of course, the FDA will still need to maintain a rigorous regulatory process, particularly when it comes to managing clinical trials.

Not only are clinical trials increasingly undertaken in developing countries — many of which have a poor capacity for ethical review — their management is also increasingly being outsourced to private companies. Both trends raise ethical concerns that require ongoing consideration by the FDA.

Funding and commitment

Drug development is also an expensive process. The Stop TB Partnership estimates that less than half of the estimated US$56 billion needed to eliminate TB by 2015 will actually be available.

TB experts can learn much from colleagues working on HIV. In the late 1980s and early 1990s, HIV advocates pushed hard for research funding and, later, for access to the life-saving antiretrovirals that were developed.

The fight against TB needs the same commitment. Securing millions of dollars in today's shaky financial environment, where even HIV programmes are suffering, will not be easy.

Through the CPTR, TB researchers have an opportunity to unblock a stagnating TB drug development pipeline with an innovative approach to research. They owe it to millions of people to take it.

Journalist Priya Shetty specialises in developing world issues including health, climate change and human rights. She has worked as a news editor at New Scientist, assistant editor at The Lancet, and commissioning editor at SciDev.Net.